I have read on here or other forums that you will loose a little bottom end. I have Thorley headers, intake and a flowmaster exhaust but with a stock cat.. I lost a little bottm end torque, but it accelerates alot better and will cruise 75-80 in 5th with 33s and 3.73 all day long.
98 TJ,4.0, 5 SPD, 4' SPRINGS,RC 2.2, SYE W/ TW DRIVE SHAFT, JKS ARMS,JKS ADJ. TRACK BARS, CURRIE ANTIROCK, ACOS ADJ, REAR D44 W/ DISC BRAKES, 62 MM THROTTLE BODY, POISON SPYDER SLIDERS, LED TAIL LIGHTS, K&N INTAKE, THORLEY HEADERS, FLOWMASTER EXH,H4 CONVERSION, 35" BFG AT